Television tube assemblies, methods of forming such assemblies and implosion guards therefor



Marsh 23, E BULCRAIG ETAL 3,311,70Q

TELEVISION TUBE ASSEMBLIES, METHODS OF FORMING SUCH ASSEMBLIES ANDIMPLOSION GUARDS THEREFOR Filed June 6, 1965 5 Sheets-Sheet 1 Inventorsm 1967 w. R. BULCRAIG ETAL 3,311,70G

TELEVISION TUBE ASSEMBLIES, METHODS OF FORMING SUCH ASSEMBLIES ANDIMPLOSION GUARDS THEREFOR Filed June 6, 1963 3 Sheets-Sheet 2 nvenlorS WMtor/W? March 28, 1967 w. R. BULCRAIG ETAL 3,311,700

TELEVISION TUBE ASSEMBLIES, METHODS OF FORMING SUCH ASSEMBLIES ANDIMPLOSION GUARDS THEREFOR Filed June 6, 1963 5 Sheets-Sheet 5 F/GJ.

United States Patent 3,311,7llt3 TELEVISION TUBE ASSEMEELIES, METHGDS 0FPURE/ENG SUCH ASEMBLEE AND IMPED- SlGN GUARDS THEREFGR William RaymondBulcraig, Freseot, and Walter Roy Blood, Huyton, near Liverpool,England, assig'nors to Pilkington Brothers Limited, Liverpool, England,a company of Great Britain Filed .lune 6, i963, er. No. 236,091 Claimspriority, application Great Britain, dune 7, 1962, 22,124/ 62 1 Claim.(Cl. 178--7.82)

This invention relates to television tube assemblies.

As a protection to a viewer of a television set, there is normallyprovided in the front of the set cabinet and between the cathode raytube, which is the television tube, and the viewer, a transparent screenwhich prevents fiying fragments, which will occur when the tubeimplodes, from leaving the set in the direction of any viewer. Such atransparent screen is known as an implosion guard, and is conveniently aglass screen or guard.

By shaping the implosion guard to the shape of the tube, the depth ofthe cabinet may be decreased, and various methods have hitherto beenemployed for locating a shaped implosion guard in position in thetelevision set. One method has been to clamp a glass screen in spacedrelation from the face or screen of the television tube, and thisclamping has been effected by using a metal harness. However, a specialharness of this kind has required expensive escutcheon pressings, andalso provides an exposed metal surface which is liable to obtain a highpotential, and consequently special earthing arrangements have to beadded or special covering arrangements used in order to protect theoperator.

Another method which has been used is to separate the implosion guardfrom the surface of the cathode ray tube by forming in the gap betweenthe guard and the tube a sandwich layer of polymerised resin material.The polymerised resin thus holds the guard in a desired relationship tothe tube, but the assembly of a guard and a tube using a resin is anexpensive and messy operation.

It is a main object of the present invention to provide a televisiontube assembly and a method of assembling a tube and an implosion guardin a desired relationship, which substantially avoids the maindisadvantages of the methods and arrangements used hitherto.

According to the present invention, there is provided a television tubeassembly comprising a television tube, and an implosion guard oftoughened transparent glass consisting of a tray formation, including adouble curvature base matching the end formation of the tube, and acontinuous boundary wall adapted to surround the end of the tube andprovide an annular space between the wall and the corresponding Wall atthe end of the tube, said space being furnished with a gasket formed toprovide lateral and axial cushioning of the end of the tube on the tray.

Preferably the gasket comprises a band portion fitted over theperipheral wall of the end of the tube and an integral beading lyingbetween the margin of the front face of the tube and the base of thetray.

The present invention also comprehends an implosion guard of toughenedtransparent glass for use in a television tube assembly according to theinvention, the implosion guard comprising a tray formation including adouble curvature base matching the end formation of the tube and acontinuous boundary Wall adapted to surround the end of the tube.

The implosion guard includes locating means on the continuous boundarywall thereof and preferably the locating means is comprised by a lug ateach of the four dfillfidd Patented Mar. 28, 1967 corners of thecontinuous boundary wall, each lug being adapted to engage the interiorof a cabinet to locate the implosion guard therein, the guard protrudingthrough the cabinet by a distance determined by the position of the lugson the said continuous boundary Wall.

Experiments have shown that a television tube assembly according to theinvention and having an implosion guard with the characteristicsindicated may be assembled by a method which is very simple andstraightforward and comparatively quick to operate.

According to this aspect of the invention, therefore, there is provideda method of assembling a television tube in a television set, comprisingfitting into the set cabinet an implosion guard of toughened glass whichprotrudes through the cabinet by a distance determined by locating meanson the guard bearing against the inside of the cabinet, and nesting theface of the tube in the back of the guard through a spacer gasketsurrounding the sides of the face of the television tube.

The invention will be more clearly understood from the followingdetailed description of one embodiment thereof, which is made by way ofexample, with reference to the accompanying drawings in which:

FIGURE 1 is an exploded view in part section showing the integers of atelevision tube assembly and part of the front of a cabinet in which theassembly will be located,

FIGURE 2 also shows in part section the television tube assembly ofFIGURE 1 in position in a television set cabinet,

FIGURE 3 is an enlarged sectional view of a portion of the televisiontube assembly of FIGURE 2, showing the configuration of the gasketportion, and

FIGURES 4 and 5 show the method of assembling the television tubeassembly according to FIGURE 2.

In the drawings like reference numerals designate the same or similarparts.

Referring to the drawings, there is indicated generally at 1 animplosion guard of toughened transparent glass which comprises a portion2 of a tray formation and a continuous boundary Wall 3. The trayformation 2 is a double curvature base, that is to say a base havingaxes of curvature in two dimensions at right angles and the doublecurvature of the base matches the end formation of the television tube4. Consequently the double curvature of the base corresponds to thedouble curvature of the screen of the television tube 4.

The continuous boundary wall 3 has a radius from the centre of theimplosion guard 1 in excess of the outer radius of the television tube 4so that the continuous boundary Wall of the implosion guard is adaptedto suitround the end of the tube.

The implosion guard 1 is made of toughened glass, and the degree oftoughening of the implosion guard is such as to enable the guard towithstand the forces to which the guard is subjected when implosion of atelevision tube occurs. These forces are the pressure wave directed fromthe outside of the television set towards the interior of the televisiontube and impacts which will occur on the side of the implosion guardnext to the television tube from flying fragments of the televisiontube.

Consequently the degree of toughening of the implosion guard must besuch as to give strength against a force bending the implosion guardagainst the curvature of the tray formation 2 and also to give strenthagainst flying fragments striking the concave surface of the trayformation 2 when a television tube implodes.

The gasket 5 is provided to maintain the implosion guard 1 in a desiredrelationship to a television tube 4- when the members are assembled toform the television tube assembly. The gasket 5 may be of rubber or offoamed synthetic resin material, for example foamed polystyrene, and thegasket comprises a band portion 6 of such size as to fit over theperipheral wall of the end of the television tube 4 and within thecontinuous boundary wall 3 of the implosion guard 1. The gasket 5further comprises a beading 7 integral With the band portion and which,in the assembled position, lies between the margin of the front face ofthe tube 4 and the base of the tray formation 2 of the implosionguard 1. The configuration of the gasket 5 can be seen in greater detailfrom FIGURE 3.

There is also shown in FIGURE 1 a portion 8 of the front of the cabinetin which the television tube assembly is mounted.

FIGURE 2 shows the television tube assembly comprising the implosionguard the television tube 4 and the gasket 5 in position in the cabinetwith the implosion guard protruding through the cabinet 3. The gasket 5provides lateral and axial cushioning of the end of the tube 4 on thetray portion 2 of the guard 1 and also acts to prevent dust penetratinginto the space between the implosion guard and the tube 4. The distanceby which the implosion guard 1 protrudes through the cabinet 8 isdetermined by the position of lugs 9 on the implosion guard 1, therebeing a lug 9 at each of the four corners of the continuous boundarywall of the implosion guard 1.

The television tube assembly is maintained in position in the cabinet bya support band 10 which extends around the television tube 4 and alsoengages locating members 11 mounted on the inside of the set cabinet.

The method by which a television tube assembly is assembled in a setcabinet will now be described, with particular reference to FIGURES 4and 5.

FIGURE 4 is a view of the portion of the interior of the set cabinet 8,showing the implosion guard 1 being located in position. This is donesimply by the operator pushing the implosion guard through the openingin the front wall of the cabinet 8 until the lugs 9 bear against theinside of the front cabinet 8.

The television tube 4 has the gasket 5 positioned thereon so that theband portion 6 of the gasket is fitted over the peripheral wall of theend of the television tube 4 and the integral beading 7 lying on themargin of the front face of the tube 4 as indicated in FIGURE 5. Thetelevision tube 4 with the gasket 5 fitted thereto is then introducedinto the cabinet in the assembled position indicated in FIGURE 2 of thedrawings with the gasket 5 surrounding the sides of the face of the tube4, until the face of the tube is nested in the back of the guard throughthe gasket 5, and the support band 10 shown in FIG- URE 2 is thensecured to maintain the television tube assembly in position.

The method of assembling a television tube in a cabinet according to thepresent invention is much more economical in time as well as in thematerials used. The

A. necessity for special earthing arrangements is avoided and at thesame time, the appearance of the projection of the front of thetelevision tube 4 through the front of the cabinet 8 is provided and afashionable appearance of the television set is obtained.

Furthermore, the arrangement according to the invention is such that theheading 7 of the gasket 5 provides a mask which covers the objectionabledistortion which occurs at the edges of the raster of the televisiontube 4, such that in the normal operation of the set, the picturepresented to the viewer may be free of distortion other than thatarising from interference.

In addition, the television tube assembly is lighter than previousassemblies, in view of the smaller number of components involved, andthe natural tendency of a television set to be top heavy is reduced bythe use of an assembly according to the invention. In addition, theimplosion characteristic of the implosion guard according to theinvention is of a very satisfactory nature on account of the doublecurvature of the tray formation of the guard 1, which gives addedmechanical strength against the pressure wave naturally set up onimplosion of the tube.

We claim:

A television tube assembly comprising a television tube, an implosionguard of toughened transparent glass consisting of a tray formationincluding a double curvature base matching the end formation of the saidtube and a continuous integral boundary wall adapted to surround the endof the tube and having lugs extending outwardly from each cornerthereof, and a cushioning gasket comprising a band portion fitted overthe peripheral wall of the tube and lying between and in contact withthe tube wall and the boundary wall of the guard, the gasket furthercomprising an integral beading lying between and in contact with themargins of the front face of the tube and the base of the guard, thegasket being formed of a strip of resilient material having a thicknessequal to the desired space between the television tube front face andthe base of the said guard.

References Cited by the Examiner UNITED STATES PATENTS 2,470,620 5/1949Jackson 178-7.82 2,929,667 3/1960 Jackson 1787.8 3,082,513 3/1963 Bracht2202.1 3,130,854 4/1964 Casciari 178-7.82

OTHER REFERENCES TV Safety Shield of Butyrate, Wall St. Journal,Thursday, Jan. 12, 1961, p. 9.

DAVID G. REDINBAUGH, Primary Examiner.

J. A. ORSINO, Assistant Examiner.

